In general, automobiles typically measure an amount of fuel in a fuel tank using an ultrasonic wave sensor to monitor the amount of fuel in the fuel tank. A height of the fuel in the fuel tank was measured by measuring a propagation time at which the ultrasonic wave signal travels from a bottom of the fuel tank to a surface height of the fuel.
In regard to this, the content of using an ultrasonic wave sensor to measure a height of fuel in a fuel tank is disclosed in Korean Patent Laid-Open Publication No. 10-2015-0091140 (published on Aug. 7, 2015, hereinafter, referred to as the related art). However, the related art has a problem that it is difficult to accurately measure the height of the fuel because a time at which an ultrasonic wave generated from the bottom of the fuel tank hits a side wall of the fuel tank and returns back is distorted.
In addition, in order to install the ultrasonic wave sensor in the fuel tank, the ultrasonic wave sensor is separately attached to a fuel tank module, or the fuel tank module and the ultrasonic wave sensor are each installed in the fuel tank. Therefore, in order to install the ultrasonic wave sensor and the fuel tank module, respectively, there is a problem in that a manufacturing process and costs are increased.